Heat-resistant paints suited for various applications are well known. Major types of such heat-resistant paints include, for example, binders such as aluminum phosphate, alkaline silicate, polysilicon alkoxide, or polysilazane.
In general, most high-temperature coatings based upon silicone polymers remain soft and sticky unless they are cured at very high temperatures. Also, many such coatings cannot be used on articles that have an operating temperature above 1200° F. Furthermore, many such coatings require an additional coating of a cathodic acrylic coating on insufficiently electrically insulated surfaces. For certain applications (e.g., exhaust manifolds on engines), the adjacent surfaces need the cathodic acrylic electrocoat, but any coating deposited on the exhaust manifold must be removed prior to reaching the end user to avoid burning and creating objectionable smoke. This is typically done using a rinsing step in processing prior to the engine passing through a curing oven intended to cure all of the electrocoat on the engine.
Thus, there is still a need for coating compositions that provide coatings with desirable adherent, protective, and heat-stable properties, particularly with high electrical insulation.